Evolution of surgical risk in Crohn's disease: impact of the biologic therapy era on time to first surgery in a Bosnian tertiary referral center.

OBJECTIVE: Contemporary surgical risk data from Southeastern Europe are limited. We assessed cumulative surgical probabilities, independent predictors of surgery, and the impact of evolving therapeutic strategies in a Bosnian tertiary referral cohort. METHODS: This retrospective cohort study included 153 patients with Crohn's disease treated at University Clinical Center Tuzla between 2009 and 2023. Calendar-period analysis estimated contemporary surgical risk, while natural-history analysis characterized progression from diagnosis. Sequential multivariable Weibull regression identified independent predictors of time to first surgery. RESULTS: Cumulative probabilities of surgery at 1, 5, and 10 years were 3, 11, and 34%, respectively. Five factors independently reduced surgical risk. Early biologic therapy showed the largest effect (hazard ratio: 0.22, 95% confidence interval: 0.07-0.73; P = 0.014), followed by colonic location (hazard ratio: 0.37, 95% confidence interval: 0.16-0.81; P = 0.014), inflammatory phenotype (hazard ratio: 0.53, 95% confidence interval: 0.32-0.85; P = 0.011), diagnosis during the biologic era (≥2017; hazard ratio: 0.56, 95% confidence interval: 0.35-0.88; P = 0.013), and early azathioprine initiation (hazard ratio: 0.61, 95% confidence interval: 0.40-0.93; P = 0.022). Sequential modeling confirmed additive protective effects of therapeutic exposures. Early surgery was associated with lower subsequent biologic use than no early surgery (27.5 vs. 81.4%; P < 0.001). CONCLUSION: Surgical risk in this Southeastern European cohort aligns with Western estimates. Colonic location and inflammatory phenotype were intrinsic protective factors, whereas early azathioprine, early biologic therapy, and biologic-era diagnosis independently reduced surgical risk. These findings support early combined therapy for high-risk patients.